Process of making isobornyl esters



Patented Get. 6, 1925.

lJNlTED STATES PATENT OFFIQE.

JOSEPH EBER'I', OF HILLSIDE, NEW JERSEY, ASSIGNO'R OF ONE-THIRD TO JOHN C. IDEHLS, OF NEWARK, NEW JERSEY, AND ONE-THIRD T LEO STEIN, OF EAST ORANGE, NEW JERSEY.

PROCESS OF MAKING ISOBORNYL ESTERS.

No Drawing. Application filed May 13, 1920, Serial No. 380,953:

To all whom it may concern:

Be it known that I, JOSEPH EBER'r, a citizen of the United States, residing at Hillside, county of Union, and State of New Jersey, have invented a certain new and useful Process of Making Isobornyl Esters, of which the following is a specification.

This invention is a process of making isobornyl esters, and the object of the invention is to expedite and cheapen the manufacture of the same, as well as to increase the yield.

Isobornyl esters have been generally heretofore produced either from camphene by the method of Bertram and lValbaum or by the double decomposition of pinene hydrochloride and a fatty acid salt of a heavy metal, or by heating pinene hydrochloride with a fatty acid in the presence of metallic zinc. In carrying out these processes crystalline pinene hydrochloride has been exclusively employed. It has thus been necessary, after saturating the pinene with dry hydrochloric acid gas, to separate the crystalline pinene hydrochloride out of the mixture of pinene and dipentene hydrochlorides so produced by a troublesome and time consuming refrigerating process.

By using the herein described process, this separation is avoided, and by thus utilizing what were heretofore regarded as undesirable byproducts, the yield of isoloornylesters is greatly increased. The mass obtamed by the saturation of pinene with dry hydrochloric acid gas, consisting of a mixture of solid pinene hydrochloride and liquid dipentene hydrochloride, is dissolved in a fatty acid and this mixture is heated at a suitable temperature in the presence of metallic tin or zinc, to which a small amount of copper or iron has been added.

In carrying out this process, it is desirable that a metamerizing action, as well as a deacidifying action be carried out, and, while any suitable agents may be employed for these purposes, I have found that copper or iron serve well as metamerizers and tin or zinc as de-acidifiers, hence the use of these metals as described.

V'Vhen the method is thus practiced, the copper or iron convert the dipentene hydrochlorides into pinene hydrochloride, while the tin or zinc split off the hydrochloric acid Renewed February 19, 1925.

from the pinene hydrochloride, forming camphene. This camphene, in a nascent condition, is immediately converted into the corresponding isobornylester of the fatty acid employed, the metallic chlorides acting as catalyzers While the invention may be carried out in different ways and by the use of different apparatus, I will, for the purpose of illustration, give one example of how it may be carried out in practice.

The mixture obtained by saturating 40.8 kilogrammes of pinene with the necessary amount of dry hydrochloric acid gas, is dissolved in 130 kilogrammes glacial acetic acid; 20 kilogrammes metallic tin and two kilogrammes metallic copper are now added, bot-h metals preferably being in a finely divided form. The resulting mixture is heated in a reflux apparatus at a temperature ranging substantially from 80 C. to 119 0., but not exceeding the boiling point of the particular fatty acid employed and during this reaction the mixture is constantly stirred. The heating is discontinued as soon as a sample, after making it alkaline with a sodium hydroxide solution, yields a liquid free from chlorides. This usually takes place after heating from to hours.

In the foregoing formula, the 20 kilogrammes of tin may be substituted by 10 kilogrammes zinc, the 2 kilogrammes of copper by 2 kilogrammes of iron, although any other metamerizing or de-acidifying agent may be employed. The excess of glacial acetic acid is then distilled off under reduced pressure of 15 to 16 millimeters, and at a temperature of to C. The residue in the still is now poured into water, and stratification results. The upper layer forming the crude isobornylacetate is separated, dehydrated and distilled under reduced pressure of 15 to 18 millimeters and at a temterature of 105 to 120 C. to produce pure is-obornylactate The metals used may be recovered by any of the well known methods.

I have found that the addition of metallic copper or iron increases the yield of the esters of isoborneol by 13-16 per cent equalling about 85-90 percent of the theory.

It will be understood that the processes described may be modified as to details, or by the substitution of equivalents, without which consists in heating a mixture of pinene "hydrochloride and dipentene hydrochlorides,

and a fatty acid, at a temperature not exceeding the boiling point of the fatty acid, in the presence oi" a tie-acidifying agent and a metamerizing metal.

3. The process of making isobornylesters 'Which consists in heating a mixture of pinene hydrochloride and dipentene liydrochlorides, and a fatty acid, at'a temperature ranging substantially from 80 to 119 C, in the presence of a Clo-acidifying agent and a met'ainei'izing metal.

'4. The process of making isobornylesters which consists in heating a mixture of pinene hydrochloride and dipentene liydrochlorides, and a fatty acid, in the presence of a deacidtying metal anda metamerizing metal.

5. The process of making isobornylesters which consists in heating a mixture of pinene hydrochloride and dipentene hydrochlorides, and a fatty acid, in the presence of a deacidifying metal in finely divided form and I a metainerizing metal in finely divided form.

6. The process of making isobornylesters, which consists in heating a mixture of pinene hydrochloride, dipentcne hydrochlorides, a fatty acid, a de-acidifying agent, and a metameriziiig metal While refluxing and stirring the mixture.

7. The process of making isobornylesters, Which consists in heating a mixture of pinene hydro-chloride, dipentene hydrochlorides, a fatty acid, a metallic tie-acidifying agent for the hydrochloric acid formed and a metallic metamerizing metal in finely divided form, at a temperature not exceeding the boiling point of the fatty acid. I i

8. lThe process of making isobornylesters which consists in heating a mixture of pinene hydrochloride, dipentene hydrochlorides, and tatty ftClChlil the presence of a deacidi't'ying agent and a catalytic metal Whereby the camphene resulting is converted While in nascent condition into esters, distilling off the excess of the fatty acid under reduced pressure, and purifying the esters by separating and distilling.

9. The process of making" isobornylesters which consists in heating a mixture of pinene hydrochloride, dipentene hydrochlorides, acetic acid, metallic zinc, and a metallic inetamerizing agent at a temperature below the boiling'pointoif acetic acid.

In testimony whereoi'l have signed my name to this specification,

JOSEPH neiiiir. 

